管状(MgO)12是(MgO)n的幻数团簇,非常稳定.为研究电场对其储氢性能的影响,本文在B3LYP/6-31G**水平上研究了电场中H2在(MgO)12管状结构上的吸附性质.结果表明(MgO)12能承受强电场而保持管状结构并被极化,其偶极矩增大为场强0.01 a.u.和0...管状(MgO)12是(MgO)n的幻数团簇,非常稳定.为研究电场对其储氢性能的影响,本文在B3LYP/6-31G**水平上研究了电场中H2在(MgO)12管状结构上的吸附性质.结果表明(MgO)12能承受强电场而保持管状结构并被极化,其偶极矩增大为场强0.01 a.u.和0.02 a.u.时的9.21和19.39 deb(1 deb=3.33564×10-30C·m).H2能稳定吸附在单个Mg/O原子上.无电场时H2在Mg上为侧位吸附,而在O上为端位吸附;电场中,H2在Mg和O上均为端位吸附,且其分子取向沿外电场方向.由于(MgO)12及H2均被电场极化,因此H2在(MgO)12部分位置上的吸附强度显著提高.H2在3配位的Mg/O上的吸附能由无电场时0.08/0.06 e V分别提高到场强为0.01 a.u.和0.02 a.u.时的0.12/0.11 e V和0.20/0.26 e V.电子结构分析表明H2吸附在Mg原子上时,向团簇转移电荷,电场极化效应是其吸附能较无电场时增大的主要原因.吸附在O原子上时,一方面由于O阴离子极化效应更强;另一方面,H2从(MgO)12得到电荷,其价轨道与团簇价轨道重叠形成化学键,因此电场效应更显著.电场中(MgO)12最多能吸附16个H2,相应的质量密度为6.25 wt%.展开更多
Catalytic steam reforming of condensable vapors, i.e. bio-oil, derived from pyrolysis of biomass is an important process for hydrogen production, which is expected to form renewable and clean energy. The generation of...Catalytic steam reforming of condensable vapors, i.e. bio-oil, derived from pyrolysis of biomass is an important process for hydrogen production, which is expected to form renewable and clean energy. The generation of hydrogen from bio-oil was investigated from 250 to 750 ℃ by a MgO mixed C12A7-O^-(C12A7-MgO) catalyst in a fixed-bed micro-reactor. The hydrogen yield on C12A7-MgO was about 44% at 750 ℃. It is found that both the catalytic activity and catalysis life are improved by doping MgO. The XRD results show that the C12A7 structure of the positively charged lattice framework remains in the C12A7-MgO catalyst.展开更多
Various solid electrolytes,such as sulfides(10^-3-10^-2 S cm^-1)and oxides(10^-4–10^-3 S cm^-1)are explored and developed to solve the safety problems in commercial Li-ion batteries using liquid flammable electrolyte...Various solid electrolytes,such as sulfides(10^-3-10^-2 S cm^-1)and oxides(10^-4–10^-3 S cm^-1)are explored and developed to solve the safety problems in commercial Li-ion batteries using liquid flammable electrolytes.Metallic Li anode is required for pursuing high power density(>300 Wh kg^-1)for solid-state batteries[1,2].展开更多
文摘管状(MgO)12是(MgO)n的幻数团簇,非常稳定.为研究电场对其储氢性能的影响,本文在B3LYP/6-31G**水平上研究了电场中H2在(MgO)12管状结构上的吸附性质.结果表明(MgO)12能承受强电场而保持管状结构并被极化,其偶极矩增大为场强0.01 a.u.和0.02 a.u.时的9.21和19.39 deb(1 deb=3.33564×10-30C·m).H2能稳定吸附在单个Mg/O原子上.无电场时H2在Mg上为侧位吸附,而在O上为端位吸附;电场中,H2在Mg和O上均为端位吸附,且其分子取向沿外电场方向.由于(MgO)12及H2均被电场极化,因此H2在(MgO)12部分位置上的吸附强度显著提高.H2在3配位的Mg/O上的吸附能由无电场时0.08/0.06 e V分别提高到场强为0.01 a.u.和0.02 a.u.时的0.12/0.11 e V和0.20/0.26 e V.电子结构分析表明H2吸附在Mg原子上时,向团簇转移电荷,电场极化效应是其吸附能较无电场时增大的主要原因.吸附在O原子上时,一方面由于O阴离子极化效应更强;另一方面,H2从(MgO)12得到电荷,其价轨道与团簇价轨道重叠形成化学键,因此电场效应更显著.电场中(MgO)12最多能吸附16个H2,相应的质量密度为6.25 wt%.
文摘Catalytic steam reforming of condensable vapors, i.e. bio-oil, derived from pyrolysis of biomass is an important process for hydrogen production, which is expected to form renewable and clean energy. The generation of hydrogen from bio-oil was investigated from 250 to 750 ℃ by a MgO mixed C12A7-O^-(C12A7-MgO) catalyst in a fixed-bed micro-reactor. The hydrogen yield on C12A7-MgO was about 44% at 750 ℃. It is found that both the catalytic activity and catalysis life are improved by doping MgO. The XRD results show that the C12A7 structure of the positively charged lattice framework remains in the C12A7-MgO catalyst.
基金financially supported by Ganfeng Lithium Co., Ltd.
文摘Various solid electrolytes,such as sulfides(10^-3-10^-2 S cm^-1)and oxides(10^-4–10^-3 S cm^-1)are explored and developed to solve the safety problems in commercial Li-ion batteries using liquid flammable electrolytes.Metallic Li anode is required for pursuing high power density(>300 Wh kg^-1)for solid-state batteries[1,2].
